The item is a flight safety critical aircraft part (fscap).
A nut having 6 flat sides and an integral washer which extends beyond the flats or periphery. An integral feature is incorporated for locking on the threads of a mating member.
Classification: Nuts of iron or steel
NSN 5990-00-432-0649
NSN 6645-00-200-2322
NSN 5985-01-276-2790
NSN 4140-00-470-3590
NSN 5930-00-907-7300
NSN 6150-01-622-9741
NSN 5965-01-604-0409
NSN 5950-00-156-7287
NSN 5960-01-425-1454
NSN 5895-01-569-8083
NSN 5905-01-588-7630
NSN 5950-01-330-6995